Chlamydia trachomatis is one of the two microorganism species of the genus Chlamydiaceae, order Chlamydiales. The other species is Chlamydia psittaci. Chlamydia trachomatis in its some 15 various strains, are the etiologic agents for a number of human ocular and genital diseases including trachoma, inclusion, conjunctivitis, lymphogranuloma venereum, "nonspecific" or non-gonococcal urethritis and proctitis. C. trachomatis infection is pervasive throughout the general population. It has been estimated, for instance, that C. trachomatis is accountable for several million cases per year of nongonococcal urethritis.
Since C. trachomatis mediated disease is widespread, a reliable, simple and inexpensive test for the organism's presence is highly desirable and of great importance so that proper treatment may be undertaken. The only serological test in current use is the microimmunofluoresence test. This test however requires that the strains of C. trachomatis be used as serological test antigen. In addition, the facilities for conducting this test are available in only a limited number of laboratories throughout the world. The test is very laborious, time consuming and difficult to perform.
Recently, U.S. Pat. No. 4,118,469, noted the preparation of an antigen of C. trachomatis useful in serological testing for lymphogranuloma venereum and nongonoccocal urethritis. Such antigen was purified from C. trachomatis organisms by immunoadsorption chromatography using the monospecific antiserum as a specific ligand covalently bound in an agarose gel column. This antigen had a molecular weight of about 160,000 daltons, and in counter-immunoelectrophoresis testing was capable of detecting antibodies from the sera of lymphogranuloma venereum patients. However, when utilized in a similar test with sera of non-gonoccocal urethritis patients, this antigen failed to detect antibodies. It was successful, however, in detecting antibodies in two dimensional immunoelectrophoresis testing.
In any event, however, there is still great medical interest in the isolation of species specific antigens of C. trachomatis which are capable of the detection of C. trachomatis infection, preferably by commonly practiced antigen-antibody assay methods.